Induction of COX-2 by feline calicivirus via activation of the MEK1-ERK1/2 pathway, and attenuation of feline lung inflammation and injury by MEK1 inhibitor AZD6244 (selumetinib)

Feline calicivirus (FCV) is an important and highly prevalent pathogen of cats that causes acute infectious respiratory disease. Here it is shown in vitro that FCV induces the production of cyclooxygenase-2 (COX-2) through the MEK1-ERK1/2 signaling pathway. Screening of FCV proteins revealed that FCV non-structural protein VPg enhanced COX-2 mRNA expression and protein production in CRFK cells in a concentration-dependent manner. Regions 24-54aa and 84-111aa in FCV VPg were essential for up-regulation. In vivo, COX-2 and IL-6 production caused by FCV infection of kittens was significantly suppressed by the MEK1 inhibitor AZD6244 (selumetinib) and lung inflammation and injury were practically eliminated, with body temperature being returned to normal. AZD6244 may therefore find application as an effective therapeutic agent for the treatment of FCV infection.